This paper evaluates the performance of Wi-Fi networks for interactive Virtual Reality (VR) streaming with adaptive bitrate control. It focuses on the interaction between VR traffic characteristics and Wi-Fi link-layer mechanisms, studying how this relationship impacts key performance indicators such as throughput, latency, and user scalability. We begin by outlining the architecture, operation, traffic patterns, and performance demands of cloud/edge split-rendering VR systems. Then, using simulations, we investigate both single-user scenarios—examining the effects of modulation and coding schemes (MCSs) and user-to-access point (AP) distance on bitrate sustainability and latency—and multi-user scenarios, assessing how many concurrent VR users a single AP can support. Results show that the use of adaptive bitrate (ABR) streaming, as exemplified by our NeSt-VR algorithm, significantly outperforms constant bitrate (CBR) approaches, enhancing user capacity and resilience to changing channel propagation conditions. To validate the simulation findings, we conduct an experimental evaluation using Rooms, an open-source eXtended Reality (XR) content creation platform. The experimental results closely match the simulations, reinforcing the conclusion that adaptive bitrate control substantially improves Wi-Fi’s ability to support reliable, multiuser interactive VR streaming.

SignON, a 3-year Horizon 20202 project addressing the lack of technology and services for MT between sign languages (SLs) and spoken languages (SpLs) ended in December 2023. SignON was unprecedented. Not only it addressed the wider complexity of the aforementioned problem – from research and development of recognition, translation and synthesis, through development of easy-to-use mobile applications and a cloud-based framework to do the “heavy lifting” as well as to establishing ethical, privacy and inclusivenesspolicies and operation guidelines – but also engaged with the deaf and hard of hearing communities in an effective co-creation approach where these main stakeholders drove the development in the right direction and had the final say.Currently we are witnessing advances in natural language processing for SLs, including MT. SignON was one of the largest projects that contributed to this surge with 17 partners and more than 60 consortium members, working in parallel with other international and European initiatives, such as project EASIER and others.

SignON (https://signon-project.eu/) is a Horizon 2020 project, running from 2021 until the end of 2023, which addresses the lack of technology and services for the automatic translation between sign languages (SLs) and spoken languages, through an inclusive, human-centric solution, hence contributing to the repertoire of communication media for deaf, hard of hearing (DHH) and hearing individuals. In this paper, we present an update of the status of the project, describing the approaches developed to address the challenges and peculiarities of SL machine translation (SLMT).

Physical manipulatives, such as rods or tiles, are widely used for mathematics learning, as they support embodied cognition, enable the execution of epistemic actions, and foster conceptual metaphors. Counting them, children explore, rearrange, and reinterpret the environment through the haptic channel. Vision generally complements physical actions, which makes using traditional manipulatives limited for children with visual impairments (VIs). Digitally augmenting manipulatives with feedback through alternative modalities might improve them. We specifically discuss conveying number representations to children with VIs using haptic and auditory channels within an environment encouraging exploration and supporting active touch counting strategies while promoting reflection. This paper presents LETSMath, a tangible system for training basic mathematical skills of children with VIs, developed through Design-Based Research with three iterations in which we involved 19 children with VIs and their educators. We discuss how the system may support training skills in the composition of numbers and the impact that the different system features have on slowing down the interaction pace to trigger reflection, on understanding, and on incorporation.

The SignON project (www.signon-project.eu) focuses on the research and development of a Sign Language (SL) translation mobile application and an open communications framework. SignON rectifies the lack of technology and services for the automatic translation between signed and spoken languages, through an inclusive, humancentric solution which facilitates communication between deaf, hard of hearing (DHH) and hearing individuals. We present an overview of the current status of the project, describing the milestones reached to date and the approaches that are being developed to address the challenges and peculiarities of Sign Language Machine Translation (SLMT).

Abstract Simulating crowds requires controlling a very large number of trajectories of characters and is usually performed using crowd steering algorithms. The question of choosing the right algorithm with the right parameter values is of crucial importance given the large impact on the quality of results. In this paper, we study the performance of a number of steering policies (i.e., simulation algorithm and its parameters) in a variety of contexts, resorting to an existing quality function able to automatically evaluate simulation results. This analysis allows us to map contexts to the performance of steering policies. Based on this mapping, we demonstrate that distributing the best performing policies among characters improves the resulting simulations. Furthermore, we also propose a solution to dynamically adjust the policies, for each agent independently and while the simulation is running, based on the local context each agent is currently in. We demonstrate significant improvements of simulation results compared to previous work that would optimize parameters once for the whole simulation, or pick an optimized, but unique and static, policy for a given global simulation context.

Spherical Fibonacci grids (SFG) yield extremely uniform point set distributions on the sphere. This feature makes SFGs particularly well-suited to a wide range of computer graphics applications, from numerical integration, to vector quantization, among others. However, the application of SFGs to problems in which further refinement of an initial point set is required is currently not possible. This is because there is currently no solution to the problem of adding new points to an existing SFG while maintaining the point set properties. In this work, we fill this gap by proposing the extensible spherical Fibonacci grids (E-SFG). We start by carrying out a formal analysis of SFGs to identify the properties which make these point sets exhibit a nearly-optimal uniform spherical distribution. Then, we propose an algorithm (E-SFG) to extend the original point set while preserving these properties. Finally, we compare the E-SFG with a other extensible spherical point sets. Our results show that the E-SFG outperforms spherical point sets based on a low discrepancy sequence both in terms of spherical cap discrepancy and in terms of root mean squared error for evaluating the rendering integral.

Recent developments of video and sensing technology have led to large volumes of digital media data. Current media production relies on videos from the principal camera together with a wide variety of heterogeneous source of supporting data [photos, light detection and ranging point clouds, witness video camera, high dynamic range imaging, and depth imagery]. Registration of visual data acquired from various 2D and 3D sensing modalities is challenging because current matching and registration methods are not appropriate due to differences in structure, format, and noise characteristics for multimodal data. A combined 2D/3D visualization of this registered data allows an integrated overview of the entire data set. For such a visualization, a Web-based context presents several advantages. In this paper, we propose a unified framework for registration and visualization of this type of visual media data. A new feature description and matching method is proposed, adaptively considering local geometry, semiglobal geometry, and color information in the scene for more robust registration. The resulting registered 2D/3D multimodal visual data are too large to be downloaded and viewed directly via the Web browser, while maintaining an acceptable user experience. Thus, we employ hierarchical techniques for compression and restructuring to enable efficient transmission and visualization over the Web, leading to interactive visualization as registered point clouds, 2D images, and videos in the browser, improving on the current state-of-the-art techniques for Web-based visualization of big media data. This is the first unified 3D Web-based visualization of multimodal visual media production data sets. The proposed pipeline is tested on big multimodal data set typical of film and broadcast production, which are made publicly available. The proposed feature description method shows two times higher precision of feature matching and more stable registration performance than existing 3D feature descriptors.

The benefits of applying technology to education have been often questioned. Learning through digital devices might imply reducing the children's physical interaction with the real world, when cognitive theories hold that such interaction is essential to develop abstract concepts in Mathematics or Physics. However, conflicting reports suggest that tangible interaction does not always improve engagement or learning. A central question is how cognitive theories can be successfully applied to the design of interactive systems in order to achieve enhanced learning experiences. In this paper we discuss the interaction design of a mixed-reality system for mathematics learning for school-aged children. Our design approach combines inspiration from previous frameworks with a user-centered design process with early prototype evaluations. As a result of this process we have created a mixed-reality environment for low-cost tablets and an augmented version of the Cuisenaire rods, a milestone of the manipulatives for mathematics learning.

Mixed-reality environments allow to combine tangible interaction with digital feedback, empowering interaction designers to take benefits from both real and virtual worlds. This interaction paradigm is also being applied in classrooms for learning purposes. However, most of the times the devices supporting mixed-reality interaction are neither portable nor affordable, which could be a limitation in the learning context. In this paper we propose CETA, a mixed-reality environment using low-cost Android tablets which tackles portability and costs issues. In addition, CETA is open-source, reproducible and extensible.

While most of today’s children, young people, and adults are both consumers and producers of digital content, very little is known about older people as digital content creators. Drawing on a three-year ethnographic study, this paper reports on the digital video production and appropriation of approximately 200 older people (aged 60–85). They generated 320 videos over the course of the study. We show their motivations for engaging in digital video production, discuss their planned video making, and highlight their creativity while editing videos. We show the different meanings they ascribed to digital videos in their social appropriation of these objects, the meaningful strategies they adopted to share videos, and the impact on their perceived wellbeing. Furthermore, we outline the solutions the participants developed to overcome or cope with interaction issues they faced over time. We argue that the results portray older people as active and creative makers of digital videos with current video capturing, editing, and sharing technologies. We contend that this portrayal both encourages us to re-consider how older people should be seen within human–computer interaction and helps to frame future research/design activities that bridge the grey digital divide.

A typical high-end film production generates several terabytes of data per day, either as footage from multiple cameras or as background information regarding the set (laser scans, spherical captures, etc). This paper presents solutions to improve the integration of the multiple data sources, and understand their quality and content, which are useful both to support creative decisions on-set (or near it) and enhance the postproduction process. The main cinema specific contributions, tested on a multisource production dataset made publicly available for research purposes, are the monitoring and quality assurance of multicamera set-ups, multisource registration and acceleration of 3-D reconstruction, anthropocentric visual analysis techniques for semantic content annotation, and integrated 2-D–3-D web visualization tools. We discuss as well improvements carried out in basic techniques for acceleration, clustering and visualization, which were necessary to deal with the very large multisource data, and can be applied to other big data problems in diverse application fields.

In this paper, we present a web-based application allowing the analytic visualisation of on-set media data and metadata, which combines research from several fields of image processing and 3D graphics. Film and television production is currently undergoing a paradigm shift, away from the concept of capturing a `shot' with a single principal camera view, to recording everything possible about the set, the environment, the objects and the actors within it. In parallel, the rise of cloud-based storage and processing is pushing towards applications being controlled via web or browser based interfaces. The application presented in this paper has been created to meet both of these needs, visualising Big Media Data via a web-based interface, and supporting the integration of multiple data formats and analysis. We discuss the different modalities and processing included in the current tool, stress the integration into the web and the solutions to the challenges posed, and show how the tool has been initially tested by professionals, with positive outcomes.

Recent research in the Game-Based Learning domain shows that location-based games can lead to positive effects in studentsâ?? motivation and engagement. However, the potential effectiveness of these approaches depends on to what extent their design is aligned with the requirements of specific educational situations. For this reason, involving teachers in the design of their own location-based learning games becomes crucial to fulfil their teaching requirements. This paper presents a metaphor based on puzzle boards as a technique to involve teachers in the design of their own location-based games. A design-based research methodology has been followed to evaluate the proposed metaphor. Previous research experiments have shown the feasibility of the puzzle-based games approach to allow secondary education teachers the design of these types of learning experiences. However, some issues in terms of understanding specific elements of the proposed metaphor were detected. A second iteration of the research methodology is described in the paper to evaluate the changes made to the definitions of the metaphorâ??s elements and the dynamics of the game design task. The evaluation is carried out with 20 primary and secondary education teachers who completed a paper-based design task. The main findings show that teachers did not have problems using the proposed metaphor and they successfully designed their own location-based learning games.

Consumer-grade head-mounted displays (HMD) such as the Oculus Rift have become increasingly available for Virtual Reality recently. Their high degree of immersion and presence provokes usually amazement when first used. Nevertheless, HMDs also have been reported to cause adverse reactions such as simulator sickness. As their impact is growing, it is important to understand such side effects. This paper presents the results of a relatively large scale user experiment which compares using a conventional game controller versus positioning in the virtual world based upon the signal of the internal Inertial Measurement Unit (IMU) using Oculus Rift DK1. We show that simulator sickness is significantly reduced when using a position estimation system rather than using the more traditional game controller for navigation. However the sense of presence was not enhanced by the possibility of 'real walking'. We also show the impact of other factors, such as prior experience or motion history, and discuss the results.

Educational games have been proved to be learning environments that are more in correspondence with new generation of students since they can provide successful learning and motivate students in their learning process. In this line, several studies describe the main factors that games should have in order to design engaging learning experiences. Taking into account these factors, this paper presents the design of three different game-based learning environments providing hints for puzzle solving different tasks within the area of computer architecture, programming fundamentals, and computing networks. An evaluation carried out with secondary and higher education students provides further considerations regarding the design of hints, score, and supportive learning material that should be taken into account when creating such kind of games.

Mobile technologies are currently being applied to facilitate the development of learning activities in diverse spaces beyond the classroom. Indoors and outdoors spaces are augmented with located digital Educational Resources (ER) through specific technologies that provide a sensory input to smart phones that can indicate position and, thus, enable located learning activities. The potentiality that smart phones have, make these devices adequate to facilitate the access to located ERs. This paper proposes four space-aware design factors (the space, the connectivity, the position-based technologies and the guidance) that have to be considered for designing located learning activities supported with smart phones. The application of the factors is explained through four illustrative located learning scenarios. The paper discusses and provides a wide-range vision of how the combination of these factors affects the design of the activity, accessing to the ERs and monitoring the students' progress.

This article reports on an exploratory study aimed to identify which ways of marking required and optional fields help older people fill in web forms correctly. Drawing on a pilot study and selective attention research in ageing, modified versions of widely used forms were created, in which standard asterisks were replaced with one of three alternatives: large asterisks (double standard size), textual labels and a simple binary classification of fields. Older novice computer users participated in this study (N = 88). The quantitative results were independent of the type of form and showed that the method of denoting required fields had a significant effect on the number of errors (measured as required fields not being filled (p < 0.05)). The participants made fewer errors in the binary classification than in the others (p < 0.05), while the differences between standard asterisks, large asterisks and labels were not significant (p > 0.05). The qualitative findings revealed that the participants felt overloaded with information when using every method except the binary classification. These results challenge widespread design solutions for older people (e.g. enlarging elements) and suggest that reducing selective attention demands can help us meet their accessibility needs.

Speech prosody has traditionally been analyzed in terms of acoustic features. Even though visual features and gestures have been shown to help and enhance linguistic processing, the conventional view is that facial and body gesture information in oral (non-sign) languages tends to be redundant and has the role of helping the hearer recover the meaning of an utterance. We conducted two perception experiments with a 3D animated character showing conflicting auditory and visual information to investigate two related questions regarding the importance of gestures in conveying prosodic meaning: (a) how important are facial cues with respect to auditory cues for the perception of contrastive focus?; and (b) what is the relevance of the different gestural movements (i.e., head nod and eyebrow raising) for the perception of this type of focus? Our findings reveal that the visual component is crucial in the semantic interpretation of contrastive focus.

Based on a 3-year ethnographical study, this paper discusses the prolonged use of computer-mediated communication (CMC) tools by approximately 400 older people in an adult education centre in Barcelona (Spain). Contrary to oversimplified views of older people as ICT users, this paper shows that they make a very rich use of CMC tools. Relevant elements of this use are their permanent desire to feel and be included, social, independent and competent ICT users. Despite the numerous interaction issues they face when using ICT, some are constant across different tools. Difficulties due to cognition limit their interactions more severely than those problems due to perceiving visual information or using the mouse. By examining the longitudinal aspect of the study, this paper addresses the evolution of technology use and whether the interaction issues that most of the current older people exhibit will be relevant when today’s more ICT literate young adults grow older. Interaction issues due to cognition are time-persistent, and independent of both experience and practice with ICT. Difficulties reading from the screen or using input devices are overcome with ICT experience. The strategies adopted by older people for coping with all these interaction issues are always targeted at feeling and being included, social, independent and competent ICT users. The results deepen current understanding of tools use in connecting older people with their social circles and the interaction issues most of them encounter when using ICT. The results also suggest that cognitive-related problems will be the most important ones in our work with the next generation of older people.

Nowadays professional journalists create and edit broadcasting materials inside newsrooms that are characterized by an intense and multivariate flux of information. Within these settings, the journalists have difficulties keeping up with the evolving geopolitical picture of events developing in the world and how it relates to the topics of their interest. In this paper we present AmbientNEWS, an ambient display that visualizes dynamic news content and informs professional journalists on the global picture of events. We argue that the conceptualization and design of its information aesthetics criteria can be grounded in user requirements, and subsequently engaged to augment the awareness of professionals in an environment that is highly crowded with information. We also discuss the evaluation process of ambient information visualization with a focus on aesthetic design aspects. We conclude by summarizing our findings and discuss future work.

Personal development plans (PDP) have positive effects in learnerspsila motivation and confidence since they enable individuals to reflect upon their own learning and to plan for their own educational development according to their personal interests, background and experience. Despite those benefits, there are not many efforts considering the role of learners in the creation of their own learning paths. In this paper we adopt the approach of concept mapping to propose and implement a visual approach for supporting learners in the exploration of existing learning paths and the creation of their PDP. The paper also describes a user study for preliminarily evaluating the implemented tool and discusses the most significant findings around three main issues of interest: understanding of the tool purpose, suitability of the graphic elements shown in the interface, and changes or additions that would improve the usability of the tool.

With the aim of visually supporting learners in the creation of their personal development plans, this paper describes the functionalities added to a preliminary approach for improving its usability and satisfying better the learnerspsila needs taking into account the findings from a previous user study.

The management of groups is an essential task in collaborative learning scenarios. In a blended learning situation, in which online activities and face-to-face activities are combined, this group management becomes more complex. Different technological solutions have been proposed for supporting the group management in the CSCL field. However, these approaches fail to consider factors inherent to the blended learning scenarios. In this paper we discuss and propose a conceptualization of the main factors that condition the group management in these scenarios: the pedagogical method, the participants, the space and the history. These new conceptualization may help on incorporating more flexibility and accuracy on the whole learning design process for a wide range of learning situations.

Scripts are the computational solution proposed in the computer-supported collaborative learning (CSCL) field to guide and support potentially fruitful interactions in terms of learning benefits. However, when applying these scripts to real contexts, unexpected situations occur that forces to change the script on the fly. In a blended learning situation, in which online activities and face-to-face activities are combined this changes becomes more complex. Different solutions and tools have been developed to provide support to collaborative practices. However, these systems are still too rigid to capture the unexpected changes and situations that can occur in educational contexts. Specialized and interoperable tools should be developed for supporting these changing situations, without spoiling natural group dynamics.

With the aim of facilitating teachers the use of good techniques in computer assisted assessment, this paper proposes the integration of rubric functionalities in an editor compliant with the IMS question and test interoperability specification (QTI). Teachers can organize the information of an e-questionnaire using the QTI-rubric approach. They can use (and reuse) QTI elements without having a technical background or knowledge of the specification. The QTI-rubric enables automatic formative feedback for learners and the results can serve them as a personal evidence of their knowledge and capabilities.

With the aim of facilitating teachers the design of units of learning and assessment, this paper proposes the use of different educational pattern types. Depending on the type of patterns, the resulting didactic materials are specified using IMS Learning Design or IMS Question and Test Interoperability extended with integrated Web2.0-like services.

The success of Web 2.0 technologies in providing support for social interaction in educational spaces depends on how learning environments benefit from the affordances of Web 2.0 services. These services can be combined with the management of learning activities as done by IMS Learning Design (IMS LD) compliant systems. In this paper, we analyze the ability of an integrated system (blog, forum, and IMS LD activities) to instigate and support learner activity and interaction with other members of the learning network. This analysis takes the form of a case study in which a small professional learning community uses the integrated system. Four different aspects are studied in this case: The role of the tutor, the role of socially outgoing learners, the influence of the adopted educational approach, and the system's components. The paper explains how each of these aspects can play a role in augmenting learner activity and interaction, and consequently incrementing the success of learning systems.

This paper presents research carried out toward the improvement of current virtual environments from an intelligent systems approach. A novel architecture to solve vague queries that allows users to find objects and scenes in virtual environments is described. As a base, a new virtual worlds representation model and an associated fuzzy querying approach are used. The new representation model adds a semantic level to the usual models, providing more suitable environments for the interaction with users. The query solver is able to work with queries expressing the vagueness inherent to human conceptualization of visual perception (for example, tall tree, a park with many tall trees, or a park bench near approximately five tall trees). The system has been developed and evaluated with user experiments, where comparison with navigation and keyword-based query approaches have been realized. The results of this study show that the proposed architecture is more powerful and intuitive for finding the targets.

In this paper we present the Planet Project. Its main goal is focused on educational content generation and wide-area distribution. For that matter, we have designed a distributed content repository (PlanetDR) which has been built on top of a structured peer-to-peer grid middleware called Dermi. The system has been made with interoperability in mind and it thus follows the IMS Digital Repositories Interoperability standard through an implementation of the eduSource Communication Language protocol. PlanetDR has been extended to support a federation mode, which to the best of our knowledge constitutes the first attempt in providing an alliance of content repositories throughout a structured peer-to-peer grid. Moreover, we have also created several collaborative tools which will he integrated in the content's life cycle in order to promote knowledge communities around educational content hierarchies. Subsequently, we have developed PlanetDR Communities which allow researchers to easily locate themselves by their own keywords of interest, which are stored and looked up in a peer-to-peer grid decentralized infrastructure.

The IMS-QTI, and other related specifications have been developed to support the creation of reusable and pedagogically neutral assessment scenarios and content, as stated by the IMS Global Learning Consortium. This paper discusses how current specifications both constrain the design of assessment scenarios, and limit content reusability. Also suggest some solutions to overcome these limitations. The paper is based on our experience developing and testing an IMS QTI Lite compliant assessment authoring tool, QAed. It supports teacher centering, which is quite neglected when designing such tools. In the paper, the author also discuss how to make compatible standards support and user centering in eLearning applications and provide some recommendations for the design of the user interfaces.

In this paper we propose to apply emergent collective behavior ideas to automatically program Internet multichannel radio stations. The proposed model simulates n virtual Dj's (one per channel) playing songs at the same time. Every virtual Dj takes into account the songs played by the other ones, programming a sequence of songs whose order is also coherent. That is, every song played in a channel takes into account both, the song previously played in the same channel and the songs being played in the other channels at the same time